Safety device for kick presses



July 9, 1940. J. w. LYNCH SAFETY DEVICE FOR KICK PRESSES Filed Aug. 4,1937 Patented July 9, 1940.

PTENT OFFICE SAFETY DEVICE FOR KICK PRESSES John W. Lynch, Chicago,llll., assignor to Chicago Flexible Shaft Compa y, Chicago, 111., acorporation of Illinois Application August 4, 1937, Serial No. 157,353

'3 Claims.

This invention relates to safety devices, and has special reference to asafety device particularly adapted for use on kick presses and analogoushand fed devices.

' A large number of accidents in maufacturing plants are occasioned bycarelessness or unfamiliarity of the operators of presses andthe like,and considerable difficulty in this connection'is experienced inassembly departments and similar places where small jobs are performed,such as small riveting and similar jobs which are commonly accomplishedby manually operated devices such as kick presses. In the case of thelatter machines, the operators will frequently kick the lever, bringingthe plunger down Without first removing their fingers from beneath theplunger. Various devices have been used on the presses, but'so far as Iknow, none of them have been successful in completely eliminatingaccidents of this character. For example, some of these devices haveoperated satisfactorily when .the

press is allowed to go through its normal complete operation, but whenthe operator deviated somewhat from the normal succession of events,then frequently the safety device failed to grant complete protection.

. The object of the invention is the provision of ous use of both handsfor its release and requiring the maintenance of the locking means inthe released position at all points in the plunger stroke toward itsengaged position.

Other objects will be apparent from the fol-,

lowing description and the accompanying drawing, in which Figure 1 is aside view of a conventional kick press showing the manner in which thesafety device is applied;

Fig. 2 is a fragmentary front view of the press showing the safetydevice applied thereto;

Fig. 3 is a section on the line 3--3 of Fig. 2, and

Fig. 4 is a view on the line 44 of Fig. 2.

For the purpose of illustrating the invention I have shown the same inconnection with a conventional form of kick press which per se formspedal 1 for rotation of the same about a pivot point 8. The frame 5carries a slide or plunger 9 reciprocated' by ahead II in response tomovement of the treadle 6, the lower end of the plunger carrying a diepunch- [2. A die shoe I3 is positioned on the frame 5 opposite the punch12, and is adapted to be engaged thereby at the lowermost point in thestroke of the plunger 9 to perform the desired work. The upper end ofthe plunger 9 has a rod It carrying the usual limit stop l5 adapted toengage a projecting portion it of the frame 5 to limit the movement ofthe punch toward the die.

The safety device includes a. plate I! attached to the plunger 9 bymeans of cap screws i8 and it and spaced therefrom by means of spacers2i and 22, the plate being positioned on the forward side of the plunger9. Dowels 23 and 24 serve to retain the parts in position. Ratchet teethare positioned on opposite edges of the plate H as shown at 25 and 2%,the two rows of teeth extending therealong a distance slightly greaterthan the throw or stroke of the plunger 9. Attached to the frame 5 onopposite sides of the plunger 9 are handles 21 and 28 projectinglaterally outward, as best shown in Fig. 2, the handles beingarticulated on bolts 29 and 3! and spaced from the face of the frame 5by spacing blocks 32 and 33. The bolts 29 and iii are interconnected bya strap 34 retained in position by nuts 35 and :26, intermediate theends of the bolts 29 and 3|. The handles 2! and 28 are movable betweenthe full line and dotted line positions shown in Fig. 2, and on theirinner ends carry detents 31 and 38 positioned to engage the ratchetteeth 25 and 26, respectively, of the plate 11. The detents have pins 39and 4! extending from the front sides thereof interconnected by a spring42 tensioned to normally pull the detents into engagement with theratchet teeth. The plate ll, ratchet teeth. 25 and 26, and the detents31 and 38, and spring 42 are enclosed within a cover 43 attached to theframe 5 through the bolts 29 and 3|, nuts 44 and 45 serving to retainthe cover against the frame.

It will be seen that the handles 21 and 28 are so spaced as to requireseparate hands for their actuation in order to release the detents 31and 38 from the ratchet'teeth. Thus, in operation, the work is placedonthe dieshoe l3 by the operator, but the pedal 1 cannot be pushed forwardin order to move the plunger 9 to its lower tents 31 and 38.

or operative position until the handles 21 and 28 have been moved totheir dotted line position shown in Fig. 2. In order for the operator tomove the plunger to the operative positions it is necessary that thehandles 21 and 28 be grasped in the two hands and pulled to the dottedline position, under which circumstances it is impossible for the handto be caught between the die punch and the die. However, when theplunger has reached its operative position the plunger can return to itsuppermost position after the handles have been released because of theratchet arrangement of the teeth 25 and 26 and the de- In operation,frequently the operator will not go through with the entire operationbut may stop the pedal a part of the way back in the swing, but if atthis point either hand is removed from the handles 21 and 28, theplunger is immediately locked at, any point in its swing against furtherengagement movement until the hand is replaced on the handle. It will beobserved that the handles 21 and 28 must be held in the lowermostposition during the entire engaging movement of the plunger, and

if at any time during such movement, either hand is removed, the spring42 will cause one of the detents to be drawn into the ratchet teeth andthe downward movement of the plunger to be stopped.

The above description and the accompanying drawing are believed toconvey a full disclosure of the invention in conformity with the patentlaws.

I claim:

1. A safety device for kick presses of the type having a plungercomprising a plate attached to the plunger, movable therewith andsecured against longitudinal movement with respect thereto, said platehaving spaced rows of ratchet teeth thereon extending through theamplitude of the plunger stroke, spaced handles rotatably supported on astationary part of the press for rotation between engaged and disengagedpositions, spring means for normally holding the handles in the engagedpositions, and detents on said handles adapted to engage said teeth inthe engaged position of the handles and to disengage the teeth when thehandles are moved to the disengaged position against the tension of thespring, said handles being mounted tomove in a plane parallel with thefront of the press and being spaced at such distance as to require bothhands of the operator for their simultaneous actuation to hold saiddetents out of engagement to permit movement of said plunger to theoperative position, whereby movement of the plunger toward saidoperative position will be stopped upon removal of either hand from thehandles.

2. A safety device for kick presses of the type having a movable plungerelement and a stationary supporting element therefor comprising at leastone row of teeth attached to one of said elements and extendinglongitudinally of said plunger, detents attached to the other of saidelements arranged to engage the teeth at any point in the stroke of theplunger to thereby prevent longitudinal movement of the plunger towardits operative position and to ratchet thereon in return movement of theplunger, spring means for normally maintaining said detents inengagement, and a pair of handles for selectively moving said detentsout of engagement with said teeth, said handles being mounted to swingin a vertical plane parallel with the face of the press and being spacedapart a distance such as to require both hands of the operator for theiractuation to efiect downward movement of the plunger and whereby to stopmovement of the plunger toward its operative position upon the removalof either hand from the handles.

3. A safety device for presses and the like having a stationary supportand a plunger element movable vertically thereon in a stroke between anormal at-rest position and a finished operative position, vertical rowsof teeth on the plunger element, and a hand lever on the stationarysupport adjacent to each row of teeth and having a detent arranged toengage the teeth at any point in the stroke of the plunger to therebyprevent longitudinal movement of the plunger at any point in its stroketoward its said operative position and to ratchet on said teeth inreturn movement of the plunger, said detents being constantly urged intoengagement with said teeth and adapted to be withdrawn only whenratcheting and upon downward manual operation of the handles, saidhandles being arranged for operation only in a plane parallel with thefront of the press, whereby to necessitate the use of both hands of theoperator in the downward movement of said handles in said plane towithdraw said detents and permit operation of the plunger element in adownward stroke, and whereby to stop movement of the plunger elementtoward its said operative position upon the removal of either hand fromthe handles.

JOHN W. LYNCH.

